The present invention relates to audio signal processing, and, in particular, to an apparatus and a method for improving speech intelligibility in background noise by amplification and compression.
In many speech communication applications (e.g., public address systems in train stations or mobile phones) it is of great interest to maintain high speech intelligibility even in situations where speech is disturbed by additive noise and/or reverberation. One simple approach to maintain that goal is to amplify the speech signal prior to presentation in order to achieve a good signal-to-noise ratio (SNR). However, often such simple amplification is not possible due to technical limitations of the amplification system or unpleasantly high sound levels. Therefore, algorithms that improve the speech intelligibility while maintaining equal output power compared to the power observed at the input are desirable. This invention comprises an algorithm that is capable of increasing the speech intelligibility in scenarios with additive noise without increasing the overall speech level.
Other signal processing strategies that go beyond simple amplification have been presented in the literature (see [1], [2], [3], [5], [6]).
However, it would be very appreciated if improved signal processing concepts for speech communications applications would be provided.